I work shift work and sometimes take melatonin. i also work out a few hours before bed. is it safe to take melatonin before a workout in this case?

Melatonin use: Typically melatonin is used to assist in sleep. When you take it in relation to the work out is important. IF it starts working quickly you will feel tired during the workout. Its always better to take it after the workout.

Take before sleep: Melatonin is useful to adjust your sleep wake cycle as you do shift work. It also has a sleep-inducing effect. For both these reasons it is probably better and safer to take it closer to your sleep time and not before your workout